Intake Air Temperature Sensor

On 1996-00 vehicles, the Intake Air Temperature (IAT) sensor is monitors the temperature of air entering the engine. As the temperature of the air entering the engine rises, the resistance of the IAT sensor decreases. The signal sent to the PCM by the IAT sensor is used for on board diagnostics only, and does not affect engine operation. IAT sensors are not used on 1993-95 vehicles.

Fig. The IAT sensor is located in the air cleaner intake tube

Fig. The tip of the IAT sensor has a thermistor that changes the resistance of the sensor based upon the temperature of the incoming air

Removal & Installation

Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

Disconnect the negative battery cable.

Disconnect the IAT sensor electrical connector.

Remove the sensor from the air cleaner intake tube.

The installation is the reverse of removal.

Fig. IAT sensor connection-1996-00 vehicles

Testing

Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

Turn the ignition switch
OFF
.

Disconnect the wiring harness from the IAT sensor.

Measure the resistance between the sensor terminals.

Compare the resistance reading with the accompanying chart.

If the resistance is not within specifications, replace the sensor.

Fig. Another method of testing the IAT sensor is to submerge it in cold or hot water and check resistance